BEIRUT -- Syrian rebels pushed into a strategic neighbourhood in the northern city of Aleppo after days of heavy clashes, seizing control of at least part of the hilltop district and killing a pro-government cleric captured in the fighting, activists and state media said Saturday.

There were conflicting reports about the scale of the advance into the Sheikh Maqsoud neighbourhood by rebel forces battling to topple Syrian President Bashar Assad. But the gains marked the biggest shift in the front lines in the embattled city in months.

Aleppo, Syria's largest city and a former commercial hub, has been a key battleground in the country's civil war since rebels launched an offensive there in July, seizing several districts before the fighting largely settled into a bloody stalemate.

The Aleppo Media Center opposition group and Aleppo-based activist Mohammed Saeed said rebels seized full control of Sheikh Maqsoud late Friday.

The Britain-based Syrian Observatory for Human Rights, however, said rebels took only the eastern part of the neighbourhood, and reported heavy fighting there Saturday.

Syria's state news agency SANA said government troops "eliminated scores of terrorists" in other parts of Aleppo mainly in the neighbourhoods of Sheikh Said, Masaken Hanano and Bustan al-Bacha. SANA did not mention the fighting in Sheikh Maqsoud.

Sheikh Maqsoud, which is predominantly inhabited by minority Kurds, is located on a hill on the northern edge of the city. The neighbourhood used to be known as "Our Lady's Mountain" and is considered one of the most strategic locations in the city because it overlooks much of Aleppo.

Activists predicted that regime forces would launch counterattacks to try to retake the area because if rebels keep holding Sheikh Maqsoud it will be easy for them to target regime-held areas with mortar shells.

The media centre and the Observatory both reported that residents were fleeing the neighbourhood to safer areas. The media centre said regime tanks around the neighbourhood were shelling the area.

An amateur video showed about two dozen gunmen standing in front of a building owned by the Syrian government. In the video, one of the gunmen claims that rebels and their "Kurdish brothers liberated Sheikh Maqsoud of Assad's criminal gangs and shabiha" or pro-government militiamen.

The video appeared genuine and corresponded to other reporting that The Associated Press did on events depicted in the footage.

Saeed, the Aleppo-based activist, said several rebel groups, including Kurdish gunmen, took control of the neighbourhood after launching an attack, titled "Kurdish Fraternity," on Thursday. He said that on Saturday fighting intensified on the eastern edge of the area around an army post known as Awamid.

The Observatory said rebels captured a pro-government Sunni Muslim cleric in the fighting, killed him and then paraded his body through the neighbourhood.

State-run Al-Ikhbariya TV identified the cleric as Hassan Seifeddine. It said he was beheaded and his head was placed on the minaret of Al-Hassan Mosque where he used to lead the prayers.

The SANA state news said Seifeddine's body was "mutilated" after the "assassination."

The reports of the mutilation of the cleric's body could not be independently confirmed.

The killing of Seifeddine comes nearly 10 days after a suicide bomber blew himself up inside a mosque in the heart of the Syrian capital, Damascus, killing top Sunni preacher Sheik Mohammad Said Ramadan al-Buti as he was giving a sermon. The March 21 blast killed 48 others and wounded dozens.

Al-Buti, like Seifeddine, was a strong supporter of the Assad regime, which is dominated by members of the president's minority Alawite sect, an off-shoot of Shiite Islam. The opposition is made up of mostly Sunnis, who are the majority among Syrians.

Extremists have been playing a larger role among the rebel groups. They include the Islamic Jabhat al-Nusra, a powerful offshoot of al-Qaida in Iraq, which has claimed responsibility for most of the deadliest suicide bombings against regime and military facilities and, as a result, has gained popularity among some rebels.

A photograph recently posted online by activists showed Seifeddine, who was in his late 50s and had a white beard. A banner posted over the picture said: "A wanted agent." Another referred to him as wanted by the rebels and read: "An agent of Syria's ruling gang and wanted by the Free Syrian Army."

Aleppo-based Sunni cleric Abdul-Qadir Shehabi told state-run TV that Seifeddine's son was kidnapped months ago. Shehabi also lashed out at the rebels, saying they "mutilated" Seifeddine's body.

"Is this the freedom that they talk about? This is the freedom of Satan," Shehabi said, referring to rebels who say they are fighting Assad's regime because it is authoritarian.

Rami Abdul-Rahman, who heads the Observatory, said Seifeddine's name had been put on an opposition "death list."

"He was the imam of a mosque. He was not armed when he was killed," Abdul-Rahman said. "We cannot close our eyes when the opposition violates human rights."

Abdul-Rahman said that although Sheikh Maqsoud is predominantly Kurdish, the eastern areas where much of the fighting occurred are inhabited by pro-regime Sunni Muslims known as the "Mardilis." Many of them came to Aleppo decades ago from Turkey's southeastern province of Mardin. He said Seifeddine was one of them.

Elsewhere in Syria, activists reported violence in areas of the southern province of Daraa, the suburbs of Damascus and the northern regions of Idlib and Raqqa. The Observatory said the heaviest clashes were in Raqqa and Sheikh Maqsoud.

Abdul-Rahman said the fighting in Sheikh Maqsoud killed 14 pro-government gunmen, seven rebels, 10 civilians and Seifeddine.

The Observatory said rebels were fighting a fierce battle around an army post known as the Camp in the oil-rich eastern province of Deir el-Zour, which borders Iraq.

In Damascus, residents said power was cut on Saturday in some neighbourhoods. Al-Ikhbariya TV quoted Minister of Electricity Imad Khamis as saying the network suffered a technical problem that would be fixed in 24 hours. Damascus has witnessed repeated cuts in recent months.